P1780
DTC P1780
Circuit Description
The powertrain control module (PCM) determines when the vehicle is in Park or Neutral gear position through the park/neutral position (PNP) switch. The RED/BLK wire to the PCM is grounded by the PNP switch when the transmission manual selector is in either Park or Neutral gear position.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1780 Park/Neutral Position (PNP) Switch Circuit
Conditions for Setting the DTC
^ Engine speed changed from below 300 RPM to over 500 RPM when the vehicle speed is 0 km/h (0 mph) and the PNP switch is open-R, D, 2 or Liters gear positions.
^ The PNP switch closed/P or N gear position is detected for 10 seconds while the engine is running at over 2,500 RPM and with more than 38.5 percent calculated load value.
Action Taken When the DTC Sets
The malfunction indicator lamp (MIL) will illuminate with the fault active.
Conditions for Clearing the DTC
^ The MIL will turn OFF after 3 consecutive drive cycles without a fault present.
^ DTC will clear after 40 consecutive warm-up cycles without a fault.
^ DTC can be cleared by using a scan tool or by disconnecting the PCM battery feed.
Diagnostic Aids
Inspect for the following conditions:
^ The PNP switch, for proper operation
^ Poor connection at the PCM connector C3, the PNP switch connector, and at connector CZ10. Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection.
^ Damaged harness-Inspect the wiring harness for damage.
^ If DTC P1780 cannot be duplicated, the information included in the freeze frame data can be useful in determining vehicle operating conditions since the DTC was last set. This may assist in determining how often the DTC sets.
DTC Confirmation Procedure
The DTC Confirmation Procedure outline is here as follows:
1. Turn the ignition switch to LOCK.
2. Connect the scan tool to data link connector (DLC).
3. Start engine and warm-up to normal operating temperature.
4. Use a scan tool in order to clear the following items from the PCM memory:
^ The DTC
^ The pending DTC
^ Freeze frame data
5. Drive the vehicle to 43 km/h (27 mph) in Drive range for 10 seconds.
6. Accelerate the vehicle to 85 km/h (53 mph) in Drive range for 10 seconds.
7. Stop the vehicle.
8. Use the scan tool in order to inspect for DTC P1780.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
1. The Diagnostic System Check - Vehicle, prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. This step checks the Liters position signal circuit.
3. This step checks the N and the P position signal circuit.
4. This step checks the P position signal circuit.
5. This step checks the R position signal circuit.
6. This step checks for poor terminal contact at the PCM.
7. This step checks for a faulty PCM.
8. This step checks for a short to voltage in the Liters position.
9. This step checks for a short to ground in the Liters position.
10. This step checks for an open in the Liters position.
12. This step checks for a short to voltage in the N and P positions.
13. This step checks for a short to ground in N and P positions.
14. This step checks for an open in N and P positions.
15. This step checks for a short to voltage in the 2 position.
16. This step checks for a short to ground in the 2 position.
17. This step checks for an open in the 2 position.
18. This step checks for a short to voltage in R position.
19. This step checks for a short to ground in R position.
20. This step checks for an open in R position.
Step 1 - Step 10:
Step 11 - Step 21:
